Motor driven camera focusing mechanism

ABSTRACT

An electrically conductive pendulous member is mounted on a camera for operation in response to the principle of triangulation and for selective positive displacement into any operative condition by a manually actuatable control mechanism. Upon displacement of the pendulous member into engagement with a conductive portion of a carrier means, a motor of a lens focusing mechanism is energized to cause simultaneous adjustment of the lens and the carrier means until the lens is in an &#39;&#39;&#39;&#39;in-focus&#39;&#39;&#39;&#39; condition. A secondary indicator circuit informs the user when a focusing operating is complete.

[451 May 1, 1973 United States Patent [1.91

Freeland [541 MOTOR DRIVEN CAMERA FOCUSING 3,572,230 3/1971Freeland...............................95/44 C MECHANISM v PrimaryExaminerSamuel S. Matthews [75] Inventor. Stanley R. Freeland, Glenvlew,[11. Assistant Examiner Michael D- Harris A ttorney-John E. Peele, Jr.et a1.

[73] Assignee:

Bell & Howell Company, Chicago,

[57] ABSTRACT An electrically conductive pendulous member is [22 Filed:

Sept. l3, 1971 Appl' 179,862 mounted on a camera for operation inresponse to the principle of triangulation and for selective positivedislacement into any operative condition by a manuall actuatable controlmechanism. Upon displacement of the pendulous member into engagementwith a con- U.S. Cl.........................95/44 R, 95/45, 352/140352/140 ductive portion of a carrier means, a motor of a lens Field ofSearch focusing mechanism is energized to cause simultaneous adjustmentof the lens and the carrier means until the lens is in an in-focuscondition. A secondary inthe user when a focusing UNITED STATES PATENTSdicator circuit informs operating is complete.

3,538,831 11/1970 Mueller................................95/44C3,538,833 1l/1970 Koeber.................................9S/44C 15Claims,4DrawlngFigures Patented Ma 1, 1973 gill/49 fluenced member by aMOTOR DRIVEN CAMERA FOCUSING MECHANISM The present invention relates toa camera focusing mechanism, and particularly, to a mechanismfunctioning on the principle of triangulation for adjusting a focusablelens of a camera in response to focal distances determined bythemechanism. The lens is adjusted responsive to the orientation of agravity inmotor energized through control circuitry.

The triangulation principle relates to the determination of the lengthof one side of a right triangle, herein corresponding to a base linealong which the camerato-subject distance is measured. To compute thedistance, the height of either the vertical side or the length of thehypotenuse of the triangle, and one of the angles other than the rightangle must be known. For use of the principle in a camera focusingarrangement, the length of the vertical side of the triangle may beempirically determined as the eye level height of an average adult userabove the supporting plane or base line on which the user stands. Uponalignment of the base of a remote subject with a reference mark in theviewfinder of the camera, the camera is caused to be angled bydeterminable amounts. That is, the user views the subject at the pointwhere a vertical line through the subject intersects the supportingplane causing the optical axis of the cameras lens to be oriented at agiven angle relative to both the vertical side and the base line of thetriangle. Hence, the required mathematical values necessary to computethe unknown length of the base line are available.

The present invention seeks to eliminate the need for mathematicalcomputation by the user by providing a mechanism which functions tofocus the lens on a semiautomatic basis. To'determine the angle ofinclination of the optical axis, apendulous member, oriented under theinfluence of gravity, is arranged to pivot about an axle-which extendsperpendicularly of the optical axis. When the user sights the base of asubject at infinity, the optical axis remainssubstantially parallel witha base line on which both the subject and the user are effectivelysupported. Hence, the pendulous member remains substantiallyperpendicular to the horizontally oriented optical axis. However, if theuser 'sight's the base of a near subject, the optical axis and camerahousing will be inclined relative to the horizontal base line. As thehousing is inclined, the pendulous member, if free, will remain fixed inspace continuing to hang vertically under the influence of gravity, andwill be displaced from the optical axis by a given angle. Since therange of angular displacements corresponding to the range of focusplanes of the lens can be determined, these values may be built into afocusing mechanism to adjust the focus of the lens for that givendistance.

Typical these describes an improvement for effecting the desired resultsin a yet more desirable manner.

The features of the invention for effecting the improvements in theelectromechanical distance determining mechanisms include a gravityoriented member arranged for movement relative to the housing of .acamera or other optical instrument having a focusable objective lensassembly. The gravity oriented member, typically a pendulum, isdisplaceable positively between a free position in which it can beoriented at an angle relative to the optical axis of the lens, and afocusing mode position. For movement to the latter position, a manuallyactuatable control member is arranged to engage the pendulum fordisplacement without arcuate movement into contact with a conductorcarrier. The pendulum is in an electrical circuit with a lens adjustingmotor which is reversibly energizeable through at least two conductorplates on the carrier,

when the pendulum is in contact therewith. Upon energizing of the motor,the lens and the carrier are driven until the circuit is de-energized asthe conductor plate is moved relative to the conductive pendulum fordisengagement. At this orientation, a signal device informs the userthat lens focus has been achieved.

An object of the present invention is to provide a novel and improvedpowered focusing mechanism for a camera having a focusable objectivelens.

. Another .object is to provide a camera with a powered focusingmechanism having a positive acting actuator to selectively energize thefocusing mechanism.

Further and other objects will be apparent from the IN THE DRAWINGS FIG.1 is a perspective view of an optical instrument incorporating themechanism of the present invention with parts broken away and partsremoved for clarity;

FIG. 2 is a sectional view taken along section line 2- 2 ofFlG. 1;

FIG. 3 is an exploded perspective view of certain components of thefocusing'mechanism of the present invention; and v FIG. 4 is a schematicdiagram of the circuitry associated with the focusing mechanism. I

Referring now more particularly to the drawings, there is shown aportion of an optical instrument, such as a camera 10, having a housing12 including at least one side wall 14 and a front wall 16. The housingencloses a viewfinder system (not shown) having a reference markrelative to which the base of a viewed subject may be aligned. Adistance determining or focusing mechanism 20 is enclosed withinhousing12 for adjustment of the focus condition of a focusable objective lens22 mounted to the front wall 16 of the housing l2. Focusing of theobjective lens .is accomplished by movement of a focusing lens elementor cell, shown typically in FIG. 2 as element .24. v

A change of the distance between the camera and the subject changes theplane on which the image formed by the objective lens 22 is focused.Thus, to 7 enable adjusting the focal plane on which an image is focusedinto coincidence with the generally f xed film plane of the camera, theobjective lens 22 is capable of being focused for a range ofcamera-to-subject distances. The distance determining mechanism iscoupled with the objective lens 22 to control translation of the lensbarrel 26. As thebarrel is rotatably translated, the focusing cell 24moves axially of optical axis 28 defined by the objective lens to aposition wherein a focus condition of the lens corresponds to thecamera-to-subject distance determined by the focusing mechanism.

To adjust the focus of the objective lens 22, a drive means, shownschematically in FIGS. 1 and 4 as a small reversible DC motor 30, issupported within the camera housing 12. A drive transmission 34,indicated sche- 'matically in FIG. 4, couples the motor to a drivablecomponent of either the focusing mechanism or the lens assembly. Asshown in FIG. 1, the transmission may include a pinion 36, fixed to adrive shaft of the motor, and arranged for drivably engaging a gear 42about the lens barrel 26. By selective completion of circuit ry as thefocusing mechanism 20 reacts when in a focusing mode but a non-focusedcondition, the motor 30 is energized by a power source, shown as abattery pack 44. Motor operation drives gear 42 to cause translation offocusing lens cell 24 axially along optical axis 28 until a focuscondition is attained by the focusing mechanism. The focusing mechanism20 includes a gravity oriented, pendulous member 48 which is supportedfor free swinging movement about an axle which is one diameter of amulti-diameter threaded shaft member 50 combining an assembly screwspacer and the support axle. Another diameter of this shaft member isthreaded into a mechanism support plate 54 within the camera housing 12.Rotation of the camera housing, as occurs upon sighting the base of aremote subject, causes the pendulous member 48 to be continuouslyoriented into a vertical position under the influence of gravity. Fixedon the pendulous member for 'movementtherewith is a yieldable andelectrically conductive contact plate '56 having a ledge portion 58which extends over a complementary shaped ledge portion 60 of thependulous member. A pair of tabs 64 extend from opposite edges of thecontact plate. A conductive pin 68 is fixed to the contact plate 56 in aposition spaced from the axis about which the pendulum swings so as toestablish an arcuate path in accordance with the swinging movement.

Adjacent the inner face of the pendulous member 48 and mounted forrotation about a bearing diameter of the threaded shaft 50 is aconductor support plate or carrier 70. The conductor carrier, preferablyformed of electrically nonconductive material, is provided with a shaftreceiver, shown as cut-out 72. A pair of spaced conductor sheets 74, 76are mounted on the surface of the carrier facing the pendulous memberand preferably are recessed to be flush with that surface. Conductiverivets 78 are attached to each ,sheet and pass through the carrier toconnect the respective conductor sheets in the circuitry shownschematically in FIG. 4. On the carrier between the adjacent edges ofthe conductor sheets, a surface portion or flat 82 is formed having awidth slightly greater than the diameter of the conductive pin 68 of thependulous member 48. A pin'receiver, shown as a detent 84 in the flat ofthe carrier, is arranged in the arcuate path of movement of the pin toentrap same and positively prevent further relative movement betweenthese components.

Also attached to the carrier is a secondary conductor 88 having aportion thereof aligned with the pin receiver 84. The secondaryconductor is connected to an indicator circuit, shown schematically inFIG. 4, ineluding a power source 90, and an indicator, shown as a lamp92, which when energized might be visible in the not shown viewfinder ofthe camera.- Assuming the focus mechanism to be in focusing mode and tohave reached a focus condition, the pin 68 of the pendulous member 48energizes the indicator lamp upon passing through the pin receiver andmaking contact with the secondary conductor 88.

As shown in FIG. 2, a cam follower lug 94 extends from the rear surfaceof the carrier to engage in a cam track 96 formed about the focus barrel26 of the objective lens 22. Rotation of the focus barrel by the motor30 causes simultaneous axial displacement of the lens focus cell 24 andtracking of the cam follower lug 94. As the axially varying cam trackmoves relative to the follower lug 94, the carrier 70 is caused to pivotabout the axis through shaft 50. A resilient means shown as a coiledspring 98, has its core about the shaft 50, with one end 102 against themechanism support plate 54, and a second end 104 engaging andcontinuously urging the carrier in one direction such that the camfollower lug 94 is maintained against one edge of cam track 96.

An actuating mechanism is provided within the camera housing to controlthe operation of the focusing mechanism 20. A control button 112 extendsexternally of the housing 12 for manual actuation between an operativeor focusing mode position and an inoperative position. In this preferredembodiment, a biasing member, shown as spring 114, is connected betweena post 116 fixed in the housing, and the control button. The spring 114biases the slidably supported button 1 12 toward the inoperativeposition, yet yieldably permits actuation of the button to theoperative'position. Integral with the external button portion is aninternal body portion shown as'a spacing stud 118 attached to themechanism support plate for supporting the button within the housing forguided sliding'movement. On'an externally directed surface of the bodymember of .the' control button is formed 'awedge-like camming surface124 connecting two levels of the body portion.

Additional to the control button, the actuating mechanism 110 comprisesa shifter assembly 126 which functions relative to the pendulous member48 as a displacing means and lock. The shifter assembly includes apendulous member contact portion 128, faced with a pad of resilientmaterial 130, which enables effectively positive engagement of the tabs64 of the pen dulous-member by slight depression of the tabs into thepad. When so engaged, the pendulous member cannot be inadvertentlydisplaced about the axle portion of the shaft 50 on which it issupported. That is, the pendulous member functions as an orientationposition storage member for programming the circuitry through theconductor carrier, and will be held against rotation while the carrier70 is drivably adjusted to an orientation in agreement with focuscondition of the objective lens. Upon initial engagement of the shiftermember onto tabs 64, the pendulous member 48 is displaced axially on theshaft 50 so that the conductive pin 68 will engage either one of theconductor sheets 74, 76 of the carrier or the flat 82 therebetween. Theaxial displacement of the pendulous member is efiected by pivoting ofthe shifter member about a pivot axle 134 passing through a pair ofaligned wing portions 136 be'nt from the elongated body of the shifter.The pivot axle is mounted in axle support portions 138 which are fixedto the mechanism support plate 54. These support portions permit theshifter portion to rotate about the axle without lateral shifting and orangular pivoting relative to the axle, which latter movements mightcause inaccurate translation of the position of the pendulous memberrelative to the conductor carrier.

.Actuation of the shifter member 126 is translated from the controlbutton 1 12 by a rider button 140 fixed to the end of the shifteropposite the pendulous member engaging end. The rider button ispositionedin a path along which control button v112 is shiftable. Whenthe control button is at the inoperative position under the biasing ofspring 114, the rider button 140 engages the lower level of the controlbutton relative to camming surface 124. Upon actuation of the controlbutton 112, the rider button of the shifter is effectively displaced bythe wedge-like camming surface until the rider rides on the upper levelof the control button surface. This shifting action of the cammingportion pivots the opposite end of the shifter into engagement with thependulous member until focusing is complete.

After a focusing operation, and upon release of the control button 1 12,a small leaf spring 144, attached to the mechanism support plate 54,urges the shifter toward pendulum released orientation. That is, releaseof the control button 112 permits retraction of the shifter 128 by thespring 114 and enables the rider button 140 to effectively descend onthe wedge in response to the leaf spring 144. As th e shifter iswithdrawn from the pendulous member 48, the circuits are interrupteduntil the next focusing operation.

Referring to FIG. 4, the schematic circuit of the electrical arrangementis shown wherein the motor 30 is arranged to be energized when theconductive pendulous member 48 engages either of the conductor sheets 74or 76. Since the battery pack 44 is center tapped, cur-' rent flow inthe control circuit is reversed depending upon which of therespectiveconductor sheets is engaged. Thus, the circuit through therespective sheets causes the motor to drivably rotate the lens towardits in focus condition and to rotate toward the flat 82 between thesheets. Rotation of the carrier in either direction stops when the motor30 is deenergized as the pin 68 moves from the conductor sheet onto theflat 82 of the carrier, and into the receiver 84 formed in the flat.Completion of the circuit through the secondary conductor 88 causesenergization of the indicator signal 92, which indicates that thedistance determining mechanism is centered, and the focusing operationis complete. After the user is appraised that the lens is memberrestraining shifter into the focusing mode. The control can then bereleased by the user and would remain in the first or actuationposition. Although the control may be reset immediately after focusingis complete, it need not be reset until another. focusing operation isto be initiated. The latter operation requires that the switch bereturned to the second position for a period to permit the pendulousmember to acquire an adjusted position before the shifter member isagain moved to a pendulous member restraining position by return of thecontrol to the first position. i What is claimed is:

1. In combination in a camera including a motor driven focusableobjective lens,

circuit means for controlling energization of the motor,

camera-to-subject distance determining means responsive to angularorientation of said lens relative to the base of the subject, saiddistance deter-' mining means including orientation position storagemeans for programming said circuit means,

manually actuatable means for positively actuating said storage meansfor energizing of said circuit means, and

means being positionable responsive to the focus condition of said lensand being cooperable with said storage means for tie-energizing saidcircuit means upon adjustment of said lens to focus condition by saidmotor.

2. The combination as in claim 1 wherein said circuit means includesspaced conductor portions for reversibly energizing said motor.

3. The combination as in claim 2 wherein said storage means includesgravity responsive means.

4. The combination as in claim 3 wherein said gravity responsive meansis a pendulous member supported about an axle for swinging movement.

5. The combination as in claim 3 wherein said gravity responsivemeans'includes a conductive portion movable into engagement with saidconductor'portions of said circuit means for selective energization ofsaid motor means.

6. The combination as in claim 3 wherein said actuatable means includesa slidable member having a wedge portion for shifting said gravityresponsive means between a free swinging position and a restrainedposition.

7. The combination as in claim 6 wherein said actuatable means furtherincludes a resilient surface to prevent rotational movement of saidgravity responsive means upon and during energization of said circuitmeans.

8. The combination as in claim 6 including a carrier and a cam followercooperating with a cam track about said lens for positioning saidcarrier responsive to adjustment of focus condition of said lens, saidcarrier supporting said spaced conductor portions and said means inorientation with said conductor carrier wherein said lens is in focuscondition.

10. The combination as in claim 8 wherein said actuatable meanspositively displaces said gravity responsive means into a restrainedposition in engagement with said conductor carrier for energizing saidcircuit. 7

1 l. The combination as in claim 10 wherein said circuit means includessignal means indicating agreement of the orientation of said gravityresponsive means and the focus condition of said lens.

' 12. The combination as in claim 11 wherein said signal means includesfurther conductor means energized upon relative positioning of saidgravity responsive means between said spaced conductors on said carrier.7

v 13. In combination in a camera including a focusable objective lensdefining an optical axis and motor means for adjusting focus conditionof the lens,

circuit means for controlling energization of said motor means includingspaced conductors supported on a carrier adjustable responsive to focuscondition of said lens, I distance determining means responsive toangular orientation-of said optical axis relative to the base of aremote subject including a'pendulous member 14. The combination as inclaim 13 wherein said pendulous member includes a conductive portionmovable into engagement with said conductor portions of said circuitmeans for selective energization of said motor means.

15. The combination as in claim 13 wherein said carrier includes detentmeans cooperating with said deenergizing means for maintaining saidpendulous member in orientation with said conductor carrier wherein saidlens is in focus condition.

1. In combination in a camera including a motor driven focusableobjective lens, circuit means for controlling energization of the motor,camera-to-subject distance determining means responsive to angularorientation of said lens relative to the base of the subject, saiddistance determining means including orientation position storage meansfor programming said circuit means, manually actuatable means forpositively actuating said storage means for energizing of said circuitmeans, and means being positionable responsive to the focus condition ofsaid lens and being cooperable with said storage means for deenergizingsaid circuit means upon adjustment of said lens to focus condition bysaid motor.
 2. The combination as in claim 1 wherein said circuit meansincludes spaced conductor portions for reversibly energizing said motor.3. The combination as in claim 2 wherein said storage means includesgravity responsive means.
 4. The combination as in claim 3 wherein saidgravity responsive means is a pendulous member supported about an axlefor swinging movement.
 5. The combination as in claim 3 wherein saidgravity responsive means includes a conductive portion movable intoengagement with said conductor portions of said circuit means forselective energization of said motor means.
 6. The combination as inclaim 3 wherein said actuatable means includes a slidable membeR havinga wedge portion for shifting said gravity responsive means between afree swinging position and a restrained position.
 7. The combination asin claim 6 wherein said actuatable means further includes a resilientsurface to prevent rotational movement of said gravity responsive meansupon and during energization of said circuit means.
 8. The combinationas in claim 6 including a carrier and a cam follower cooperating with acam track about said lens for positioning said carrier responsive toadjustment of focus condition of said lens, said carrier supporting saidspaced conductor portions and said means for de-energizing said circuitmeans.
 9. The combination as in claim 8 wherein said carrier includesdetent means cooperating with said de-energizing means for maintainingsaid gravity responsive means in orientation with said conductor carrierwherein said lens is in focus condition.
 10. The combination as in claim8 wherein said actuatable means positively displaces said gravityresponsive means into a restrained position in engagement with saidconductor carrier for energizing said circuit.
 11. The combination as inclaim 10 wherein said circuit means includes signal means indicatingagreement of the orientation of said gravity responsive means and thefocus condition of said lens.
 12. The combination as in claim 11 whereinsaid signal means includes further conductor means energized uponrelative positioning of said gravity responsive means between saidspaced conductors on said carrier.
 13. In combination in a cameraincluding a focusable objective lens defining an optical axis and motormeans for adjusting focus condition of the lens, circuit means forcontrolling energization of said motor means including spaced conductorssupported on a carrier adjustable responsive to focus condition of saidlens, distance determining means responsive to angular orientation ofsaid optical axis relative to the base of a remote subject including apendulous member arranged for positioning responsive to gravity when ina free swinging mode, manually actuatable means for positivelydisplacing said pendulous member from said free swinging mode to acircuit energizing mode in movement restrained engagement with saidcarrier, and means on said carrier operable responsive to the relativepositions of said carrier and said pendulous member for de-energizingsaid circuit means upon adjustment of said lens into focus conditioncorresponding to the position of said pendulous member.
 14. Thecombination as in claim 13 wherein said pendulous member includes aconductive portion movable into engagement with said conductor portionsof said circuit means for selective energization of said motor means.15. The combination as in claim 13 wherein said carrier includes detentmeans cooperating with said de-energizing means for maintaining saidpendulous member in orientation with said conductor carrier wherein saidlens is in focus condition.